1. Field of the Invention
This invention relates to a topically applied oral bandage that can be adhered to and is protective of oral mucosa and to a storage stable gel composition providing such bandage.
2. The Prior Art
Aphthous ulcers or oral canker sores are the most common oral lesions afflicting humans. These lesions tend to recur in susceptible patients, often lasting for weeks and are characterized as necrotizing ulcerations of oral mucosal tissue located on soft, non-keratinized mucosa. The lesions are painful, affect nutritional intake, and disrupt oral hygiene. They lead commonly to secondary infections by opportunistic organisms.
Various products are in use for relief of discomfort identified with canker sores and associated lesions such as fever blisters and cold sores, these products forming a protective coating or film about the source of irritation so as to prevent exacerbation of the discomfort caused by normal eating and drinking practices and to allow the lesion to heal naturally. Typically, these products are in the form of ointments and solutions for topical application to the lesions. For the treatment of canker sores, for example, these products have variously employed ingredients such as astringents of which alum and tannic acid are examples, keratolytics such as salicylic acid and anesthetics such as benzocaine.
For example, U.S. Pat. No. 5,081,158 discloses a liquid composition which forms a medicated protective film in situ on oral mucosa, the composition consisting of a medicament dissolved in a solvent such as ethanol, hydroxypropyl cellulose and an agent such as salicylic acid or tannic acid which is disclosed as reacting by esterification with the hydroxypropyl cellulose to form the film. The patent discloses at column 2, lines 27-31, that the formation of the film is specific to hydroxypropyl cellulose and that closely related alkyl or hydroxyalkyl substituted cellulose compounds such as methyl cellulose or hydroxyethyl cellulose are not suitable substitutes for hydroxypropyl cellulose.